--- /dev/null
+/* mpfr_sub_ui -- subtract a floating-point number and a machine integer
+
+Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+Contributed by the Arenaire and Cacao projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or (at your
+option) any later version.
+
+The GNU MPFR Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MPFR Library; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+MA 02110-1301, USA. */
+
+
+#define MPFR_NEED_LONGLONG_H
+#include "mpfr-impl.h"
+
+int
+mpfr_sub_ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int u, mp_rnd_t rnd_mode)
+{
+ if (MPFR_LIKELY (u != 0)) /* if u=0, do nothing */
+ {
+ mpfr_t uu;
+ mp_limb_t up[1];
+ unsigned long cnt;
+ int inex;
+
+ MPFR_SAVE_EXPO_DECL (expo);
+
+ MPFR_TMP_INIT1 (up, uu, BITS_PER_MP_LIMB);
+ MPFR_ASSERTN (u == (mp_limb_t) u);
+ count_leading_zeros (cnt, (mp_limb_t) u);
+ *up = (mp_limb_t) u << cnt;
+
+ /* Optimization note: Exponent save/restore operations may be
+ removed if mpfr_sub works even when uu is out-of-range. */
+ MPFR_SAVE_EXPO_MARK (expo);
+ MPFR_SET_EXP (uu, BITS_PER_MP_LIMB - cnt);
+ inex = mpfr_sub (y, x, uu, rnd_mode);
+ MPFR_SAVE_EXPO_FREE (expo);
+ return mpfr_check_range (y, inex, rnd_mode);
+ }
+ else
+ return mpfr_set (y, x, rnd_mode);
+}